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Carbon Dioxide

Luke Leung

Principal

Skidmore, Owings & Merrill LLP

LEEDuser Basic Member

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July 11, 2019

Received answers from below questions from NIST Andy Persily

1. Is there a preferred bookends range of CO2 for both “optimal” energy and human performances?

Andy: No

2.Is the ASHRAE ventilation of 1000-1200 ppm average, probably not based on performance, suggesting current ventilation rate is sub-optimal with cognitive performances?

Andy: As stated in that document, 1000-1200 ppm is about bioeffluent odor perception, but I wouldn’t link those concentrations with suboptimal cog performance. The evidence on that issue is far from conclusive

3. Should CO2 requirement levels vary with functions of space? E.g. exercise vs. sleep

Andy: Yes but the requirements need to be based on something specific, e.g. CO2 as a surrogate for ventilation or for bioeffluent odor control

4. Should CO2 requirement levels vary with the type of cognitive activities?

Andy: Maybe but I don’t think we are there yet

5. Should CO2 requirement levels vary with type of people? E.g. healthy vs. vulnerable

Andy: Probably but again, not enough data to support

6. Is CO2 still a good indicator of the among of people in a space?

Andy: Do you mean is it a good indicator of occupancy? If so, yes, but it is more involved than most folks realize

Hope this helps. Let’s have the longer conversation before too long

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Jeffrey Rios

Partner

AKF Group

LEEDuser Basic Member

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Thu, 07/11/2019 - 16:40

Wow, thanks for sharing Luke. Interesting, not necessarily surprising, but kind of crazy that there is such limited information and real data… Jeffrey Rios, PE, LEED AP - Partner AKF | Energy + Performance JRios@akfgroup.com | D: 646-720-9808 | akf-energyshift.com | akfgroup.com One Liberty Plaza, 165 Broadway, 22nd Floor, New York, NY 10006 Facebook | LinkedIn | Twitter | Instagram F

Luke Leung

Principal

Skidmore, Owings & Merrill LLP

LEEDuser Basic Member

0 thumbs up

Thu, 07/11/2019 - 16:56

What I thought was interesting is current ASHRAE ventilation standard will result in 1000-1200 ppm CO2 and whether that is sub-par on cognitive performance and Andy's reply is: "The evidence on that issue is far from conclusive". Interesting to see the ASHRAE position statement in light of the Harvard and LBNL studies.

Donald Posson

Vice President

SmithGroup

LEEDuser Premium Member

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Tue, 09/10/2019 - 19:17

Attached is the IRB Research Protocol for the current Harvard Cognitive Effects (COGfx) study being conducted to better understand the cognitive impact at various IEQ conditions (including CO2 levels) across hundreds of actual buildings. As discussed today, in talking with Gail Brager with CBE they have recently hired one of the Harvard Researchers and would be willing to collaborate with our group to establish any new research projects that we feel would help advance a better understanding of ideal CO2 levels to design to (including variable rates, peaks and averages over time). We can propose this at the CBE Partner Advisory Board Meeting in October. I will follow-up with Luke and see if we can propose a potential research project.

Kim Shinn

Executive Principal and Senior Wizard

TLC Engineering Solutions

LEEDuser Premium Member

62 thumbs up

Mon, 09/16/2019 - 19:26

September 2019 ASHRAE Journal article summarizes ten recent studies on carbon dioxide effects on perceived air quality, health and work performance. Authored by Wm Fisk (LBNL), Pawel Wargocki (Technical university of Denmark) and Xiaojing Zhang (Beijing University of Technology - go B-Tech!). Quick summary:

There is little evidence that CO2 levels below 5000 ppm influence perceived air quality, acute health symptoms or physiological outcomes.
The results of research on the effects of moderate CO2 levels (above 500 ppm) on human cognitive performance are not consistent.
There is substantial, but still inconsistent evidence that performance on challenging tests of decision-making and challenging flight simulations is worsened by CO2 concentrations as low as 1000 ppm.